1. Heat a large pot over medium heat. Add oil, and once it's hot, add onion, garlic, serrano pepper and corn. Stir to combine and cook for 2 to 3 minutes, until onions become soft and translucent.
2. Add chili powder, cumin and paprika and stir to combine. Turn up heat to medium-high and add chicken broth and 1 cup water, stirring to combine. Add reserved corncobs, bring to a simmer and simmer for 12 to 15 minutes.
3. Remove corncobs. Carefully ladle 2 cups of the chowder, with vegetables, into a blender and blend until smooth. (Be sure to hold down the blender's lid tightly with a towel; hot liquid will create steam pressure in blender.)
4. Add pureed chowder back to pot and stir to combine. Reduce heat to low and add cilantro, crabmeat, lime juice and salt. Stir gently and cook for 5 minutes.
5. Taste and adjust seasoning; adjust thickness by adding more water if needed.